The beauty about trading is that at any instant we can see whether or not someone made the right investment decision. If your current position is losing money that clearly was a bad investment decision. Don't teach others "how trading works" - it is pure and simple. If you are in red it means you made a bad investment decision. Period.
You're quite wrong about this.
Taking a position is a function of liquidity and position size.
The lower the liquidity and the larger the position, the higher the likelihood of a short-term loss.
So a sound investment could necessitate making an initial loss.
Therefore it's incorrect that "at any instant we can see whether or not someone made the right investment decision."
I'd suggest that since your advice is to hold off from giving advice if your position is in the red,
you hold off from offering advice on investing.